In known wood processing machines used to convert logs into chips or flakes, it has been common for the machines to include one or more cutting members mounted either on the face of a rotating disk or on the circumferential surface of a rotating drum. During operation of the machines, wood members are guided or urged into the rotating disk or drum so that the knife-like cutting members cut away chips or flakes from the wood members, and the wood members are ultimately consumed.
Such prior art cutting members are typically configured to cut a rectangular or similar cross-section out of the wood members. However, many of these configurations do not allow for efficient cutting of the wood, as they require large surges of power during the cutting stage, which necessitates the use of large motors. Therefore such prior art devices tend to be large, heavy, and expensive. Prior art devices also typically utilize cutting members which are partially recessed within the disk or drum. Although this configuration results in a structurally effective attachment between the cutting members and the disk or drum, it is disadvantageous if unprocessable foreign material is present with the wood. When such foreign material is encountered, prior art machines typically jam, and the risk of extensive and costly damage to the machine is high. One example of such recessed cutter mounting configurations is shown in applicant's U.S. Pat. No. 4,444,234 incorporated herein by reference, which discloses the use of a drum having a plurality of the knives mounted within recesses in a rotating drum. Other recessed-knife configurations are disclosed in U.S. Pat. Nos. 867,275 to Hunter, 953,630 to Lindley, 1,311,452 to Lovejoy, 3,059,676 to Kiser, 3,463,206 to Briggs, and 4,492,140 to Pano.
The presence of unprocessable material is a particular problem in processing stumps, brush and other material of the kind remaining on the site of a logging operation. Wood "hogs" used to shred such material are subject to considerable down time and damage to cutting elements when the latter encounter rocks, metal or the like. Cutting members in the past have been expensive to manufacture and sharpen, and have been resharpened for additional use. Significant expenditures of time and money have been necessary to remove the cutting members, sharpen all their edges, and reinstall them into the machine. An example of such resharpenable cutting members is shown in applicant's U.S. Pat. No. 4,569,380 incorporated herein by reference, which discloses the use of a cutting element having a plurality of resharpenable cutting elements.
It has also been known to provide such wood processing machines with cavities provided immediately in front of the cutting members, thus allowing wood chips removed by the cutting members to fall downwardly into the cavities after being cut. Such a configuration prevents the wood chips from piling up in front of the cutting member when a large wood member is encountered, thus disadvantageously pushing such a wood member outwardly and impeding the cutting action of the cutting members. Such a configuration is shown in U.S. Pat. No. 3,304,970, in FIG. 10, in which cavities 41A are provided to accept wood chips removed by cutting members 24 to accumulate during the cutting operation, only to be discharged after the particular knife associated with the particular gullet has completed its cut. U.S. Pat. No. 2,710,635, FIG. 1, also discloses cavities (not numbered) positioned in front of cutting members 25 which also accept wood chips cut from a wood member 10. Similar configurations are shown in U.S. Pat. Nos. 3,195,593 to Hall, and 2,951,518 to Cumpston, Jr. Another similar means of removing wood chips is shown in U.S. Pat. No. 3,732,907, to Nystrom, FIG. 3, in which holes 20 are provided in front of cutting members 30, which allow wood removed from wood member 14 to pass through the disc and away from the cutting members. A similar configuration is shown in U.S. Pat. No. 3,746,062 to Nystrom.
Therefore it may be seen that a need exists in the wood processing art for an apparatus which facilitates power-efficient cutting and shredding of wood products. It may also be seen that a need also exists for a wood processing apparatus which does not become clogged with processed material. A need also has existed for a wood processing machine which is subject to a minimum of damage when encountering unprocessable foreign material, and has disposable cutting members that can be replaced with a minimum of time and effort. Finally, the need always exists for such apparatuses to be simple to operate, and inexpensive to purchase and maintain.